1. Field of the Invention
This invention generally relates to the technology of forming an excellent color image in terms of coloring property and uniformity of colors that can effectively suppress bleeding and provide high quality printing. More particularly, the present invention relates to a liquid composition that can suitably be used for forming images by means of an ink-jet recording method, an ink set, a method of forming a colored section on a recording medium and an ink-jet recording apparatus.
2. Related Background Art
An ink-jet recording method is a method of driving ink to fly and adhere to a recording medium, which may typically be a sheet of paper, for the purpose of recording an image thereon. For example, Japanese Patent Applications Laid-Open Nos. 61-59911, 61-59912 and 61-59914 disclose an ink-jet recording method that utilizes an electrothermal transducer as ejection energy supply means to apply thermal energy to ink and cause the latter to generate bubbles in order to eject liquid droplets. A high density multi-orifice recording head can be easily realized by using such a method to make it possible to record high resolution and high quality images at high speed.
Meanwhile, ink that is used with a conventional ink-jet recording method normally contains water and a coloring material as principal ingredients along with a water-soluble high boiling point solvent such as glycol that is added for the purpose of preventing ink from drying in the nozzles to clog the latter. However, an image recorded on a recording medium by using such ink may not show a satisfactory fixing effect and can be short of uniformity presumably because of an uneven distribution of the filler and the sizing material on the surface of the recording medium, which may typically be a sheet of paper. On the other hand, in recent year, images formed by ink-jet recording are strongly required to show an image quality comparable to that of silver salt photography. In other words, there is a strong demand for technologies that can raise the image density, expand the scope of color reproduction and improve the color uniformity of images formed by ink-jet recording.
Under these circumstances, various proposals have been made to improve the stability of ink-jet recording and the quality of images formed by ink-jet recording. As a proposal relating to recording medium, there is a known method of applying a filler and/or a sizing material to the surface of the base paper of a recording medium. For example, a technique of applying porous fine particles that adsorb coloring materials to a base paper as filler and forming an ink-receiving layer by the porous fine particles has been disclosed. Coat paper to be used for ink-jet recording that is produced by using such a technique is marketed as recording medium.
Some major proposals that have been made to provide stable and reliable ink-jet recording methods and improve the quality of images recorded by such ink-jet recording methods under these circumstances are classified below.
(1) Methods of Adding a Volatile Solvent and/or a Penetrating Solvent to Ink:
Japanese Patent Application Laid-Open No. 55-65269 discloses a method of adding a compound such as a surfactant that enhances the penetrating effect to ink as means of accelerating the fixation of ink to the recording medium. Japanese Patent Application Laid-Open No. 55-665976 discloses the use of ink containing a volatile solvent as major ingredient.
(2) Methods of Mixing Ink and a Liquid Composition that Reacts with Ink on the Recording Medium:
Methods of applying a liquid composition that improves the formation of an image on the recording medium before or after ejecting ink and forming a recorded image for the purpose of improving the image density and the water-resistance and suppress bleeding have been proposed. For example, Japanese Patent Application Laid-Open No. 63-60783 discloses a method of causing a liquid composition containing a basic polymer to adhere to the recording medium and subsequently recording an image by using ink containing an anionic dye. Japanese Patent Application Laid-Open No. 63-22681 discloses a method of mixing a first liquid composition containing reactive chemical seeds and a second liquid composition containing a compound that reacts with the reactive chemical seeds on the recording medium. Japanese Patent Application Laid-Open No. 63-299971 discloses a method of applying a liquid composition containing an organic compound having two or more than two cationic groups in a molecule to the recording medium and subsequently recording an image by means of ink containing an anionic dye. Japanese Patent Application Laid-Open No. 64-9279 discloses a method of applying an acidic liquid composition containing succinic acid or the like and subsequently recording an image by means of ink containing an anionic dye.
Furthermore, Japanese Patent Application Laid-Open No. 64-63185 discloses a method of applying a liquid composition that makes dyes insoluble to a sheet of paper before applying ink thereto. Japanese Patent Application Laid-Open No. 8-224955 discloses a method of using a liquid composition containing cationic substances with different molecular weight distribution regions with ink containing an anionic compound. Japanese Patent Application Laid-Open No. 8-72393 discloses a method of using a liquid composition containing a cationic substance and finely pulverized cellulose with ink. All the cited patent documents describe that the disclosed methods can produce an image with a high image density, a high printing quality, a good water-resistance, an excellent color reproducibility and a good anti-bleeding effect. Additionally, Japanese Patent Application Laid-Open No. 55-150396 discloses a method of recording an image on the recording medium by means of dye ink and subsequently applying a water-resistance providing agent that can form a lake with a dye. It proposes a method of providing the recorded image with water-resistance.
(3) Methods of Mixing Ink and a Liquid Composition Containing Fine particles on the Recording Medium:
Japanese Patent Application Laid-Open No. 4-259590 discloses a method of applying colorless liquid containing colorless fine particles of an inorganic substance onto the recording medium and subsequently causing non-aqueous recording liquid to adhere to the latter. Japanese Patent Application Laid-Open No. 6-92010 discloses a method of applying a solution containing fine particles and/or a binder polymer onto the recording medium and subsequently causing ink containing a pigment, water-soluble resin, water-soluble solvent and water to adhere to the latter. Japanese Patent Application Laid-Open No. 2000-34432 discloses a recording material containing a liquid composition that by turn contains water-insoluble fine particles and ink. All the cited patent documents describe that the disclosed methods can produce an excellent image in terms of printing quality and coloring property regardless of type of paper.